Thecal plate morphology and paralytic shellfish poisoning (PSP) toxin spectra produced by three strains of a smallAlexandriumspecies isolated from the Marlborough Sounds, New Zealand were examined. Although these cells displayed minor morphological features described in the literature as characteristic of bothA. minutumandA. lusitanicum, the former designation was adopted. High performance liquid chromatography (HPLC) analysis of culture extracts showed the toxin profiles to consist predominantly of various proportions of the carbamate toxins GTX1, GTX2, GTX4, neoSTX, and STX. These toxin profiles were similar to those observed in other New Zealand isolates ofA. minutum. They were however rather different from those observed in this species elsewhere in the world though the specific toxicity of these cells (1.8–2.2pgSTX equivalents per cell) was similarly low.